Hey I was having this same issue. I have made a lot of progress and pretty much eliminated the problem doing the following (not to say your problem could be different but this is what worked for me
1. When you attempt a start, and it wants to start but doesn't, flip the on/off switch to reset the EFI. (You will hear the pump/injectors prime or whatever they are doing) then try starting again.
Repeat as necessary - but I have found this makes each subsequent "start" a bit stronger .
2. I would not doink around w the throttle much . If anything just crack the throttle open a tad as it starts to engage. (I feel it sometimes needs a bit of a push).
3. Make sure you are not running lean for some reason. I happened to have been running a bit lean due to an air leak. Technically where my air leak was I am not sure it was affecting starting or not but when I sealed it up it sure didn't hurt!
Hope this helps!!